Method of preparing organic light-emitting device, substrate for transiting inorganic layer, and organic light-emitting device

ABSTRACT

A method of preparing an organic light-emitting device having excellent sealing characteristics against external environment and flexibility.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2012-0022519, filed on Mar. 5, 2012, in the KoreanIntellectual Property Office, the content of which is incorporatedherein in its entirety by reference.

BACKGROUND

1. Field

Embodiments of the present invention relate to a method of preparing anorganic light-emitting device, a substrate for transiting an inorganiclayer, and an organic light-emitting device.

2. Description of the Related Art

Organic light emitting devices, which are self-emitting devices, haveadvantages such as a wide viewing angle, excellent contrast, quickresponse, high brightness, excellent driving voltage characteristics,and can display multicolored images.

The organic light-emitting device includes an organic emission unitincluding a first electrode, an organic layer, and a second electrode.Since the organic emission unit is vulnerable to an externalenvironment, for example, oxygen and moisture, a sealing structure thatseals the organic emission unit from the external environment is used.

Meanwhile, there is a desire to develop a thin organic light-emittingdevice and/or a flexible organic light-emitting device.

SUMMARY

According to an embodiment of the present invention, there is provided amethod of preparing an organic light-emitting device, the methodincluding: forming at least one pre-inorganic layer including a lowtemperature viscosity transition (LVT) inorganic material on a secondsubstrate; forming at least one organic emission unit on a firstsubstrate; applying an adhesive to edge portions of at least one of thesecond substrate or the first substrate; bonding the second substrateand the first substrate using the adhesive such that the pre-inorganiclayer and the organic emission unit face each other; and transiting thepre-inorganic layer to an inorganic layer to cover the organic emissionunit by performing a healing process on the pre-inorganic layer at atemperature greater than a viscosity transition temperature of the LVTinorganic material.

According to another embodiment of the present invention, there isprovided a method of preparing an organic light emitting device, themethod including: forming at least one pre-inorganic layer including alow temperature viscosity transition (LVT) inorganic material on asecond substrate; forming at least one organic emission unit on a firstsubstrate; forming at least one first organic layer on both the firstsubstrate and the organic emission unit to cover the organic emissionunit; applying an adhesive to edge portions of at least one of thesecond substrate or the first substrate; bonding the second substrateand the first substrate using the adhesive such that the pre-inorganiclayer and the first organic layer face each other; and transiting thepre-inorganic layer to an inorganic layer to cover the first organiclayer by performing a healing process on the pre-inorganic layer at atemperature greater than a viscosity transition temperature of the LVTinorganic material.

The method may further include separating the inorganic layer from thesecond substrate.

The second substrate may include glass, plastic, or metal.

The forming of the organic layer and/or the forming of the first organiclayer may include providing a curable precursor, and curing the curableprecursor.

The providing of the curable precursor may be performed by using a flashevaporator.

The curing of the curable precursor may be performed by using UV rays,infrared rays, and laser beams.

The forming of the pre-inorganic layer may include: applying a pasteincluding a powder of the LVT inorganic material to the secondsubstrate; and sintering the paste.

The forming of the pre-inorganic layer may include: applying adispersion including a powder of the LVT inorganic material to thesecond substrate by spraying; and heat-treating the dispersion.

The bonding of the second substrate and the first substrate may beperformed in a vacuum, under a reduced pressure, or in an inertatmosphere in which an influence of moisture or oxygen is substantiallyeliminated so that the space between the second substrate and the firstsubstrate is substantially maintained in a vacuum.

The viscosity transition temperature of the LVT inorganic material maybe a minimum temperature capable of providing fluidity to the LVTinorganic material.

The viscosity transition temperature of the LVT inorganic material maybe less than a minimum value of denaturation temperatures of materialscontained in the organic emission unit.

The LVT inorganic material may include a tin oxide.

The LVT inorganic material may include at least one selected from thegroup consisting of a phosphorus oxide, a boron phosphate, a tinfluoride, a niobium oxide, and a tungsten oxide.

The LVT inorganic material may include SnO; SnO and P₂O₅; SnO and BPO₄;SnO, SnF₂, and P₂O₅; SnO, SnF₂, P₂O₅, and NbO; or SnO, SnF₂, P₂O₅, andWO₃.

The transiting may be performed by heat-treating the pre-inorganic layerat a temperature between the viscosity transition temperature of the LVTinorganic material and a minimum value of denaturation temperatures ofmaterials contained in the organic emission layer.

The transiting may include heat-treating the pre-inorganic layer at atemperature between about 80° C. and about 132° C. for about 1 to 3hours.

The transiting may be performed in a vacuum or in an inert gasatmosphere.

The transiting may include scanning the pre-inorganic layer whileirradiating the pre-inorganic layer with a laser beam.

The method may further include forming at least one second organic layerbetween the second substrate and the pre-inorganic layer.

The separating the inorganic layer from the second substrate may includeseparating the second organic layer from the second substrate byirradiating the second organic layer with a laser beam.

The second organic layer may cover at least one portion of the inorganiclayer.

According to another embodiment of the present invention, there isprovided a substrate for transiting an inorganic layer including: asubstrate; and at least one inorganic layer formed on one surface of thesubstrate and including a low temperature viscosity transition (LVT)inorganic material.

The substrate may further include at least one organic layer between theinorganic layer and the substrate.

The organic layer may include a heat-resistant organic material.

The viscosity transition temperature of the LVT inorganic material maybe a minimum temperature capable of providing fluidity to the LVTinorganic material.

The LVT inorganic material may include a tin oxide.

The LVT inorganic material may include at least one selected from thegroup consisting of a phosphorus oxide, a boron phosphate, a tinfluoride, a niobium oxide, and a tungsten oxide.

The LVT inorganic material may include SnO; SnO and P₂O₅; SnO, and BPO₄;SnO, SnF₂, and P₂O₅; SnO, SnF₂, P₂O₅, and NbO; or SnO, SnF₂, P₂O₅, andWO₃.

The second substrate may include glass, plastic, or metal.

According to another embodiment of the present invention, there isprovided an organic light-emitting device including: a first substrate;an organic emission unit on one surface of the first substrate; aninorganic layer including a low temperature viscosity transition (LVT)inorganic material and covering the organic emission unit; and a secondsubstrate on the inorganic layer and being in contact with the inorganiclayer and facing the first substrate.

The organic light-emitting device may further include a first organiclayer between the inorganic layer and the organic emission unit.

The inorganic layer may be transited onto the organic emission unit tocover the organic emission unit.

The organic light-emitting device may further include a second organiclayer between the second substrate and the inorganic layer.

The organic light-emitting device may further include an adhesivebetween the first substrate and the second substrate and disposedoutside of the organic emission unit.

The viscosity transition temperature of the LVT inorganic material maybe a minimum temperature capable of providing fluidity to the LVTinorganic material.

The LVT inorganic material may include a tin oxide.

The LVT inorganic material may include at least one selected from thegroup consisting of a phosphorus oxide, a boron phosphate, a tinfluoride, a niobium oxide, and a tungsten oxide.

The LVT inorganic material may include SnO; SnO and P₂O₅; SnO, and BPO₄;SnO, SnF₂, and P₂O₅; SnO, SnF₂, P₂O₅, and NbO; or SnO, SnF₂, P₂O₅, andWO₃.

The second substrate may include glass, plastic, or metal.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and aspects of the present invention willbecome more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a schematic cross-sectional view of an organic light-emittingdevice according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a portion II of FIG. 1;

FIG. 3 is a cross-sectional view of a portion III of FIG. 1;

FIG. 4 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention;

FIG. 5 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention;

FIGS. 6A through 6J are diagrams for describing a method of preparingthe organic light-emitting device of FIG. 1;

FIG. 7 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention;

FIG. 8 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention;

FIG. 9 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention;

FIGS. 10A through 10H are diagrams for describing a method of preparingthe organic light-emitting device of FIG. 9;

FIG. 11 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention;

FIG. 12 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention;

FIG. 13 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention;

FIGS. 14A through 14I are diagrams for describing a method of preparingthe organic light-emitting device of FIG. 13;

FIG. 15 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention;

FIG. 16 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention;

FIG. 17 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention;

FIGS. 18A through 18H are diagrams for describing a method of preparingthe organic light-emitting device of FIG. 17;

FIG. 19 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention; and

FIG. 20 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention.

DETAILED DESCRIPTION

Hereinafter, the present invention will be described more fully withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.Expressions such as “at least one of,” when preceding a list ofelements, modify the entire list of elements and do not modify theindividual elements of the list.

FIG. 1 is a schematic cross-sectional view of an organic light-emittingdevice according to an embodiment of the present invention. FIG. 2 is across-sectional view of a portion II of FIG. 1, and FIG. 3 is across-sectional view of a portion III of FIG. 1.

Referring to FIGS. 1 to 3, an organic emission unit 2 is formed on onesurface of a first substrate 1, a laminate of an organic layer 3 and aninorganic layer 4, is formed on the first substrate 1 such that thelaminate covers the organic emission unit 2.

The first substrate 1 may be formed of glass, but is not limitedthereto. The first substrate 1 may also be formed of metal or plastic.The first substrate 1 may be a flexible substrate that is bendable. Inone embodiment, a bending radius of the first substrate 1 may be 10 cmor less.

The organic emission unit 2 formed on the first substrate 1 includes alaminate including a first electrode 21, a second electrode 22, and anorganic emission layer 23 interposed between the first electrode 21 andthe second electrode 22 as shown in FIG. 2.

Although not shown herein, the organic emission unit 2 includes aplurality of pixels and one pixel circuit per pixel, and the pixelcircuit may include at least one thin film transistor (TFT) (not shown)and a capacitor (not shown).

The first electrode 21 is electrically connected to the TFT.

The first electrode 21 and the second electrode 22 face each other andare insulated from each other by the organic emission layer 23. Bordersof the first electrode 21 may be covered with a pixel defining layer 24,and the organic emission layer 23 and the second electrode 22 are formedon the pixel defining layer 24 and the first electrode 21. The secondelectrode 22 may be a common electrode for covering all pixels, and thefirst electrode 21 may be formed in each pixel independent from oneanother.

The first electrode 21 may be formed by depositing or sputtering amaterial used to form the first electrode 21 on the substrate 1. Whenthe first electrode 21 is an anode, the material used to form the firstelectrode 21 may be a high work function material so as to facilitatehole injection. The first electrode 21 may be a reflective,semi-transmissive, or transmissive electrode. Transparent and conductivematerials such as indium tin oxide (ITO), indium zinc oxide (IZO), tinoxide (SnO₂), and zinc oxide (ZnO) may be used to form the firstelectrode 21. The first electrode 21 may be formed as a reflectiveelectrode using magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li),calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), or thelike.

The first electrode 21 may have a single-layered or a multi-layeredstructure. For example, the first electrode 21 may have a triple-layeredstructure of ITO/Ag/ITO, but is not limited thereto.

The organic emission layer 23 is formed on the first electrode 21.

The organic emission layer 23 may include at least one layer selectedfrom the group consisting of a hole injection layer, a hole transportlayer, a functional layer having both hole injecting and holetransporting capabilities, a buffer layer, an electron blocking layer,an emission layer, a hole blocking layer, an electron transport layer,and an electron injection layer.

For example, the organic emission layer 23 may include at least one ofCompounds 301, 311, or 321 below.

The second electrode 22 is formed on the organic emission layer 23. Thesecond electrode 22 may be a cathode, which is an electron injectingelectrode. A material used to form the second electrode 22 may be ametal, an alloy, an electrically conductive compound, which have a lowwork function, or a mixture thereof. For example, the second electrode22 may be a reflective, semi-transmissive, or transmissive electrode byforming a thin film by using lithium (Li), magnesium (Mg), aluminum(Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In),magnesium-silver (Mg—Ag), or the like. In order to manufacture atop-emission type organic light-emitting device, a transmissive secondelectrode 22 formed of ITO or IZO may be used, and various modificationsmay be applied thereto.

In a bottom emission type organic light-emitting device in which animage is formed toward the first substrate 1, the second electrode 22may be relatively thick, so that emission efficiency toward the firstsubstrate 1 may be increased.

In a top emission type organic light-emitting device in which an imageis formed toward the second electrode 22, the second electrode 22 may berelatively thin, so that the second electrode 22 may be a reflectivelayer, or the second electrode 22 may be formed of a transparentconductive material. In this case, the first electrode 21 may furtherinclude a reflective layer.

Although not shown in FIGS. 1 to 3, a protective layer may be formed onthe second electrode 22. For example, the protective layer may be formedof LiF, lithium quinolate, Alg3, or the like.

According to an embodiment described with reference to FIGS. 1 to 3, theorganic emission unit 2 is covered with a laminate of a first organiclayer 31, the inorganic layer 4, and a second organic layer 32sequentially stacked, and thus the organic emission unit 2 is sealedfrom external air by the laminate.

In this regard, the laminate contacts an environmental element 51 or 51′to surround a border of at least one of the environmental element 51 or51′ as shown in FIG. 3.

The environmental element 51 or 51′ may be undesirable particlesattached during the formation of an organic light-emitting displaydevice and may include an organic material and/or an inorganic material.For example, the environmental element 51 or 51′ may be a micro particlefrom the external environment (e.g., dust and mote existing in theexternal environment), a micro particle of a material used to form theorganic emission unit 2 and remaining on the organic emission unit 2(e.g., a micro particle formed of a material used to form the secondelectrode 22 and remaining after the second electrode 22 is formed), orthe like. The environmental element 51 or 51′ may include variousorganic materials, inorganic materials, and organic/inorganic complexes.

In FIG. 3, the environmental element 51 or 51′ may be disposed on thesecond electrode 22. Although not shown herein, other environmentalelements may be disposed within or under the second electrode 22. Theupper surface of the organic emission unit 2 may have a bent portion.Although not shown herein, other environmental elements may be formed onthe upper surface 301 of the first organic layer 31.

The environmental element 51 or 51′ cannot be removed by a wet processsuch as washing after the organic emission unit 2 is formed.

The environmental element 51 or 51′ has a size in the range of 1 μm to 5μm. The environmental element 51′, which is smaller than theenvironmental element 51, may be covered with the first organic layer31, and the environmental element 51 may be exposed through the firstorganic layer 31. In FIG. 3, the environmental elements 51 and 51′ areconceptually illustrated as two spherical particles with different sizesfor the convenience of description.

The inorganic layer 4 may cover the environmental element 51 that is notcovered with the first organic layer 31 and exposed through the firstorganic layer 31 because the thickness of the environmental element 51is greater than that of the first organic layer 31.

The first organic layer 31 may be formed of a polymer material. Thepolymer material may include an acrylic material. As shown in FIG. 2,the upper surface 301 of the first organic layer 31 may be substantiallyflat. Here, the lower surface 302 of the first organic layer 31 may notbe flat due to the bent portion of the pixel defining layer 24. Thesubstantially flat upper surface 301 and the non-flat lower surface 302are opposite surfaces of the first organic layer 31.

Since the upper surface 301 of the first organic layer 31 issubstantially flat, a thickness t31 of the first organic layer 31 at aperimeter of the environmental element 51 is substantially the same as athickness t32 of the first organic layer 31 at a portion spaced apartfrom the environmental element 51, as shown in FIG. 3. This indicatesthat the organic layer 3 may have a uniform thickness except for thebent portion of the lower surface 302 as shown in FIG. 2. Thus, theentire surface of the organic emission unit 2 may be uniformlyprotected.

The inorganic layer 4 is formed on the first organic layer 31, andaccordingly the inorganic layer 4 contacts the first organic layer 31 inthe planar direction.

The inorganic layer 4 may include a low temperature viscosity transition(LVT) inorganic material. The inorganic layer 4 may be formed by beingmelted and solidified, which will be described later.

The LVT inorganic material is an inorganic material having a lowviscosity transition temperature.

As used herein, the “viscosity transition temperature” is not atemperature where the phase of the LVT inorganic material is completelychanged from solid to liquid, but is a minimum temperature where the LVTinorganic material has fluidity, i.e., a minimum temperature where theviscosity of the LVT inorganic material changes.

The viscosity transition temperature of the LVT inorganic material maybe less than the denaturation temperature of a material contained in theorganic emission unit 2. For example, the viscosity transitiontemperature of the LVT inorganic material may be less than a minimumvalue of the denaturation temperatures of the materials contained in theorganic emission unit 2.

The “denaturation temperature of a material contained in the organicemission unit 2” refers to a temperature capable of causing chemicaland/or physical denaturation in the material contained in the organicemission unit 2, and the material may have a plurality of denaturationtemperatures according to the type and number of materials containedtherein.

For example, the “viscosity transition temperature of the LVT inorganicmaterial” and the “denaturation temperature of the material contained inthe organic emission unit 2” may indicate a glass transition temperatureTg of the LVT inorganic material and an organic material contained inthe organic layer 23 of the organic emission unit 2. The Tg may bemeasured by performing thermo gravimetric analysis (TGA) of the LVTinorganic material and the organic material contained in the organiclayer 23 of the organic emission unit 2.

For example, the Tg may be obtained from thermal analysis of thematerial contained in the organic emission unit 2 by using TGA anddifferential scanning calorimetry (DSC) in an N₂ atmosphere at atemperature ranging from room temperature to about 600° C. (10° C./min)for TGA, at a temperature ranging from room temperature to about 400° C.for DSC (Pan Type: Pt Pan in disposable Al Pan (TGA), disposable Al Pan(DSC)), and these conditions will be understood by those of ordinaryskill in the art.

The denaturation temperature of the material contained in the organicemission unit 2 may be, but is not limited to, higher than about 130°C., and may be efficiently measured via a TGA analysis of the materialcontained in the organic emission unit 2 as described above.

The minimum value of the denaturation temperatures of the materialscontained in the substrate 1 may be in the range of about 130° C. toabout 140° C. The minimum value of the denaturation temperatures of thematerials contained in the organic emission unit 2 may be, but is notlimited to, about 132° C., and may be efficiently determined bymeasuring the Tg of the materials contained in the organic emission unit2 via a TGA analysis of the materials as described above, and choosingthe minimum Tg.

For example, the viscosity transition temperature of the LVT inorganicmaterial may be about 80° C. or greater, for example, in the range ofabout 80° C. to about 132° C., but is not limited thereto. For example,the viscosity transition temperature of the LVT inorganic material maybe in the range of about 80° C. to about 120° C. or about 100° C. toabout 120° C., but is not limited thereto. For example, the viscositytransition temperature of the LVT inorganic material may be about 110°C.

The LVT inorganic material may be a single compound or a mixture of atleast two compounds.

The LVT inorganic material may include a tin oxide such as SnO or SnO₂.

If the LVT inorganic material includes SnO, the content of the SnO maybe in the range of about 20% by weight to about 100% by weight.

In one embodiment, the LVT inorganic material may further include atleast one selected from the group consisting of a phosphorus oxide(e.g., P₂O₅), a boron phosphate (e.g., BPO₄), a tin fluoride (e.g.,SnF₂), a niobium oxide (e.g., NbO), and a tungsten oxide (e.g., WO₃),but is not limited thereto.

In various embodiments, the LVT inorganic material may include:

SnO;

SnO and P₂O₅;

SnO and BPO₄;

SnO, SnF₂, and P₂O₅;

SnO, SnF₂, P₂O₅, and NbO; or

SnO, SnF₂, P₂O₅, and WO₃,

but is not limited thereto.

In various embodiments, the LVT inorganic material may include thefollowing ingredients, but is not limited thereto.

SnO (100 wt %);

SnO (80 wt %) and P₂O₅ (20 wt %);

SnO (90 wt %) and BPO₄ (10 wt %);

SnO (20-50 wt %), SnF₂ (30-60 wt %) and P₂O₅ (10-30 wt %), where theweight percent of the sum of SnO, SnF₂, and P₂O₅ is 100 wt %;

SnO (20-50 wt %), SnF₂ (30-60 wt %), P₂O₅ (10-30 wt %) and NbO (1-5 wt%), where the weight percent of the sum of SnO, SnF₂, P₂O₅, and NbO is100 wt %; or

SnO (20-50 wt %), SnF₂ (30-60 wt %), P₂O₅ (10-30 wt %) and WO₃ (1-5 wt%), where the weight percent of the sum of SnO, SnF₂, P₂O₅, and WO₃ is100 wt %.

In various embodiments, the LVT inorganic material may include SnO (42.5wt %), SnF₂ (40 wt %), P₂O₅ (15 wt %), and WO₃ (2.5 wt %), but is notlimited thereto.

If the inorganic layer 4 has the above-described composition, theviscosity transition temperature may be maintained to be lower than thedenaturation temperature of the material contained in the organicemission unit 2, so that various defects that may be formed in theinorganic layer 4 may be rectified by a healing process, which will bedescribed below.

As shown in FIG. 3, the inorganic layer 4 may include a film-formingelement 52. The film-forming element 52 may be particles of an inorganicmaterial deposited on the first organic layer 31 during the formation ofthe inorganic layer 4 and may be rectified by the healing process thatwill be described below to constitute one portion of the inorganic layer4.

As shown in FIG. 3, the environmental element 51 is surmounted with theinorganic layer 4, and thus the lower surface 402 of the inorganic layer4 may not be flat. In more detail, the upper surface 401 of theinorganic layer 4 is substantially flat. This is because the inorganiclayer 4 is formed by providing fluidity to the inorganic layer 4 duringthe healing process and solidifying the inorganic layer 4. Accordingly,the substantially flat upper surface 401 and the non-flat lower surface402 are opposite surfaces of the inorganic layer 4.

Since the upper surface 401 of the inorganic layer 4 is substantiallyflat, a thickness t41 of the inorganic layer 4 at a perimeter of theenvironmental element 51 is substantially the same as a thickness t42 ofthe inorganic layer 4 at a portion spaced apart from the environmentalelement 51, as shown in FIG. 3. This indicates that the inorganic layer4 may have a uniform thickness except for the bent portion of the lowersurface 402 as shown in FIG. 3. Thus, the entire surface of the organicemission unit 2 may be uniformly protected.

As shown in FIG. 1, the inorganic layer 4 may have a larger area thanthat of the first organic layer 31, so that all borders of the inorganiclayer 4 contact the first substrate 1. Thus, the first organic layer 31is completely covered with the inorganic layer 4. Here, since theinorganic layer 4 contacts the first substrate 1, an adhesive strengthbetween the inorganic layer 4 and the first substrate 1 is improved, andinfiltration of external air into the organic emission unit 2 may bemore efficiently blocked or reduced. Although not shown herein, theorganic emission unit 2 may further include a pixel circuit including aTFT as described above, the inorganic layer 4 may contact any insulatinglayer of the pixel circuit and, for example, the TFT. For example, aportion extending from a gate insulating layer among the layers of theTFT may contact the inorganic layer 4. In this regard, since theinsulating layers constituting the TFT is an inorganic insulating layersuch as a silicon oxide layer, a silicon nitride layer, or a siliconoxynitride layer, characteristics thereof may be the same as or similarto those when the inorganic layer 4 contacts the first substrate 1.

At least one portion of the inorganic layer 4 is covered with the secondorganic layer 32.

The first organic layer 31 and the second organic layer 32 may be formedof the same organic material. However, the present invention is notlimited thereto, and the second organic layer 32 may include aheat-resistant organic material. In this regard, the heat-resistantorganic material may have a composition that is the same as or similarto that of the first organic layer 31.

The structure of the second organic layer 32 may be formed to cover theupper surface of the inorganic layer 4 as shown in FIG. 1, but is notlimited thereto. In one embodiment, as shown in FIG. 4, the secondorganic layer 32′ may be formed to cover the entire surface of theinorganic layer 4. In this regard, a second organic layer 32′ may notcover a portion of the border of the inorganic layer 4 as shown in FIG.4, but the present invention is not limited thereto. The second organiclayer 32′ may completely cover the inorganic layer 4 including theborder thereof.

In one embodiment, as shown in FIG. 5, a second organic layer 32″ may beformed to cover the upper surface and a portion of the side of theinorganic layer 4.

The second organic layers 32, 32′, and 32″ shown in FIGS. 1, 4, and 5,respectively, may protect the inorganic layer 4 from external impact, orthe like, and compensate for the bending characteristics of theinorganic layer 4.

Although not shown herein, at least one inorganic layer and/or laminateof the inorganic layer/organic layer may further be formed to cover thesecond organic layers 32, 32′, and 32″. The inorganic layer may beformed by using the LVT inorganic material via the healing process, butis not limited thereto. A different inorganic material from theinorganic layer 4, such as a silicon-based oxide, a silicon-basednitride, an aluminum-based oxide, and/or an aluminum-based nitride mayalso be applied.

A method of preparing the organic light-emitting device of FIG. 1 willbe described with reference to FIGS. 6A to 6J.

First, at least one second organic layer 32 is formed on a secondsubstrate 11. In FIG. 6A, three second organic layers 32 are formed onthe second substrate 11, but the present invention is not limitedthereto as long as at least one second organic layer 32 is formed on thesecond substrate 11. If a plurality of second organic layers 32 areformed on the second substrate 11, a plurality of organic light-emittingdevices may be concurrently (e.g., simultaneously) prepared, therebyincreasing productivity.

The second substrate 11 may be a transparent glass substrate, but is notlimited thereto, and may instead be a plastic substrate.

The second organic layer 32 is formed on a preselected or predeterminedregion of the second substrate 11 by using, for example, a screenprinting or slit coating process. The second organic layer 32 may beformed of a transparent acrylic or heat-resistant polymer to a thicknessin the range of about 1 μm to about 100 μm, but is not limited thereto.As described above, the second organic layer 32 may be formed of thesame material used to form the first organic layer 31.

The second organic layer 32 may isolate the inorganic layer 4 from thesecond substrate 11 and/or planarize the second substrate 11, which willbe described below. The second organic layer 32 may include aheat-resistant organic material in order to prevent the second organiclayer 32 from being damaged when the inorganic layer 4 is separated fromthe second substrate 11 by using laser beams.

In various embodiments, the second organic layer 32 may have a thicknessin the range of about 1 μm to about 100 μm. As shown in FIG. 6A, sincethe second organic layer 32 is partially coated on the second substrate11, the edges of the second organic layer 32 may extent at a right anglewith respect to the surface of the second substrate 11 which isdifferent from the first organic layer 31 and will be described below.

Since the area of the second organic layer 32 is greater than that of aninorganic paste 4′ that will be described below, the second organiclayer 32 may completely cover the inorganic paste 4′. However, thepresent invention is not limited thereto. In several embodiments, thearea of the second organic layer 32 may be less than that of theinorganic paste 4′, so that the inorganic paste 4′ may completely coverthe second organic layer 32.

The second organic layer 32 of FIG. 6A that is formed as a substantiallyflat layer is an exemplary structure for preparing the organiclight-emitting device of FIG. 1, but the present invention is notlimited thereto. For example, in the organic light-emitting devicesshown in FIG. 4 and/or FIG. 5, the center of the second organic layer 32may be recessed.

Then, the inorganic paste 4′ including the LVT inorganic material may beprinted on each of the second organic layers 32 as shown in FIG. 6B.

The inorganic paste 4′ includes the LVT inorganic material. According toan embodiment, the inorganic paste 4′ includes the LVT inorganicmaterial including SnO, SnF₂, P₂O₅, or WO₃, or a combination thereof.Powder of the LVT inorganic material is mixed and melted at about 500°C. for about 1 hour, and then quickly cooled to obtain a substantiallyhomogeneous vitreous material. The vitreous material is pulverized topowder. The powder was mixed with proper amounts of a binder and asolvent to prepare the inorganic paste 4′ having a preselected orpredetermined viscosity. The binder may include ethylcellulose and thesolvent may include terpineol. The viscosity of the inorganic paste 4′may be in the range of about 10,000 CP to about 100,000 CP.

In one embodiment, the inorganic paste 4′ having a viscosity in therange of about 20,000 CP to about 100,000 CP is printed to a thicknessin the range of about 3 μm to 10 μm. The printing may be performed byusing screen printing or slit coating. In the slit coating, desiredregions may be coated by partially opening slits.

Then, as shown in FIG. 6C, the printed inorganic paste 4′ is sintered inan N₂ atmosphere, in a vacuum, or in an Ar atmosphere to remove thesolvent and binder contained in the inorganic paste 4′, and then theresultant paste is sintered by a heat-treatment to form a pre-inorganiclayer 4″. After the sintering, the surface of the pre-inorganic layer 4″has a vitreous surface having a preselected or predeterminedhomogeneity.

The inorganic paste 4′ may be a layer formed by spray-coating adispersion including the powder of the LVT inorganic material on thesecond organic layer 32. In this regard, the pre-inorganic layer 4″ maybe formed by a heat-treatment instead of the sintering and/orcalcinating of the inorganic paste 4′ formed of the dispersion.

FIGS. 6B and 6C show a method of printing the pre-inorganic layer 4″using the inorganic paste 4′, but the present invention is not limitedthereto. The LVT inorganic material may be applied onto the secondorganic layer 32 by using sputtering, vacuum deposition, low temperaturedeposition, plasma chemical vapor deposition (PCVD), plasma-ion assisteddeposition (PIAD), flash evaporator, E-beam coating, or ion plating. Inthis embodiment, the LVT material is applied only to a preselected orpredetermined region, for example, only on the second organic layer 32,using a mask.

As shown in FIG. 6D, an adhesive 12 is applied to edge portions of thesecond substrate 11. The adhesive 12 is formed in a closed loop shape inwhich the second organic layers 32 and the pre-inorganic layers 4″ aredisposed.

Then, as shown in FIG. 6E, a mother substrate 1′ on which the organicemission unit 2 and the first organic layer 31 are formed is prepared.The organic emission unit 2 is described above.

The forming of the first organic layer 31 may include providing acurable precursor of the first organic layer 31 and curing the curableprecursor.

The precursor may be a thermosetting or photocurable precursor having aviscosity ranging from about 1 cp to about 100 cp at room temperatureand a boiling point ranging from about 300° C. to about 500° C. Forexample, the precursor may be an acrylate precursor such asmono-acrylate, dimethacrylate, and triacrylate, but is not limitedthereto. The curable precursor may be a single compound or a mixture ofat least two different compounds.

The curable precursor may be provided onto the organic emission unit 2by using a flash evaporating method, but the present invention is notlimited thereto.

Then, the curable precursor provided onto the organic emission unit 2 iscured by using a known curing method. For example, the precursor may becured by UV rays, infrared rays, and laser beams to form the firstorganic layer 31, but the present invention is not limited thereto.

The thickness of the first organic layer 31 may be in the range of about1 μm to about 10 μm. If the thickness of the first organic layer 31 iswithin the range described above, at least one portion of theenvironmental element 51 or 51′ is covered with the first organic layer31, and bending characteristics of the inorganic layer 4 may beimproved.

According to an embodiment, a curable precursor mixture includingmono-acrylate, dimethacrylate, and triacrylate at an appropriate weightratio, which has a viscosity ranging from about 1 cp to about 100 cp atroom temperature, and a boiling point ranging from about 300° C. toabout 500° C., may be formed on the organic emission unit 2, as acurable precursor, by using a flash evaporating method (film-formingrate: about 200 Å/s and film-forming time: 3 to 4 min). In this regard,the curable precursor mixture is condensed to a liquid phase as soon asthe curable precursor mixture is provided onto the organic emission unit2, and thus at least one portion of the surface of the environmentalelement 51 or 51′ is surrounded by the curable precursor without anempty space between the environmental elements 51 and 51′. Then, thecurable precursor mixture provided onto the organic emission unit 2 iscured to form the first organic layer 31 by using, for example, a UVcuring device (wavelength: 390 nm and light quantity: 500 mJ).

Then, the mother substrate 1′ is disposed opposite to the secondsubstrate 11, so that each of the first organic layers 31 faces acorresponding one of the pre-inorganic layers 4″.

Then, as shown in FIG. 6F, the mother substrate 1′ and the secondsubstrate 11 are bonded to each other by the adhesive 12. The bondingprocess may be performed in a vacuum or under a reduced pressure, andaccordingly, the space between the mother substrate 1′ and the secondsubstrate 11 is vacuumed or is in a reduced pressure. For example, suchvacuum bonding may be performed in a pressure of about 20 Kpa or less.In this regard, each of the first organic layers 31 is in contact with acorresponding one of the pre-inorganic layers 4″.

The bonding process includes curing the adhesive 12 by irradiating theadhesive 12 with UV rays.

As shown in FIG. 6G, the assembly of the mother substrate 1′ and thesecond substrate 11 is turned over, and then a healing process isperformed on the pre-inorganic layers 4″, so that the pre-inorganiclayers 4″ are transited to the first organic layers 31 to form theinorganic layers 4 covering the first organic layers 31 (Refer to FIG.6H). The healing process may include first and second healing processes.

The first healing process is performed at a temperature greater than theviscosity transition temperature of the LVT inorganic material. Forexample, the first healing process may be performed by heat-treating thepre-inorganic layer 4′ at a temperature in the range of the viscositytransition temperature of the LVT inorganic material to the denaturationtemperature of a material contained in the organic emission unit 2.

Alternatively, the first healing process may be performed byheat-treating the pre-inorganic layer 4″ at a temperature in the rangeof the viscosity transition temperature of the LVT inorganic material toa minimum value of the denaturation temperatures of the materialscontained in the organic emission unit 2. Alternatively, the firsthealing process may be performed at the viscosity transition temperatureof the LVT inorganic material.

The viscosity transition temperature of the LVT inorganic material mayvary according to the composition of the LVT inorganic material, and thedenaturation temperature of the material contained in the organicemission unit 2 and the minimum value of the denaturation temperaturesof the materials contained in the organic emission unit 2 may varyaccording to the material used in the organic emission unit 2. However,they will be easily understood by those of ordinary skill in the artaccording to the composition of the LVT inorganic material and thematerial used in the organic emission unit 2, for example, by using a Tgevaluation obtained from TGA analysis results of the materials containedin the organic emission unit 2.

In several embodiments, the first healing process may be performed byheat-treating the pre-inorganic layer 4″ at a temperature in the rangeof about 80° C. to about 132° C., for example, in the range of about 80°C. to about 120° C. or about 100° C. to about 120° C., for 1 to 3 hours,for example, at about 110° C. for 2 hours, but is not limited thereto.If the first healing process is within the range described in the aboveexamples, the LVT inorganic material of the pre-inorganic layer 4″ maybe fluidized, and the denaturation of the organic emission unit 2 may beprevented.

The first healing process may be performed in a vacuum or in an inertgas atmosphere, for example N₂ atmosphere or Ar atmosphere, using an IRoven.

The LVT inorganic material contained in the pre-inorganic layer 4″ maybe fluidized by the first healing process. The fluidized LVT inorganicmaterial may have flowability. Thus, during the first healing process,the fluidized LVT inorganic material of the pre-inorganic layer 4″ flowsto surround the first organic layer 31. Accordingly, the inorganic layer4 is formed to completely surround the first organic layer 31 and bebonded to the mother substrate 1′. Since the space between the secondsubstrate 11 and the mother substrate 1′ is maintained in a vacuum, theinorganic layer 4 may be in contact with the mother substrate 1′ withoutvoids formed between them.

In addition, as shown in FIG. 3, the inorganic layer 4 is in contactwith the mother substrate 1′ so as to surround the environmental element51, and the fluidized LVT inorganic material flows into the defects suchas pin holes or voids of the inorganic layer 4. Thus, the inorganiclayer 4 from which the defects are substantially removed may beprepared.

The inorganic layer 4 may include a region having a weak binding forcebetween the environmental element 51 or 51′ and the LVT inorganicmaterial, or among the LVT inorganic materials. The region having a weakbinding force between the environmental element 51 or 51′ and the LVTinorganic material, or among the LVT inorganic materials, may provide anentry for external environmental materials such as moisture and oxygenwhile the organic light-emitting device is stored or operates to inducethe formation of a progressive dark spot, so that the lifespan of theorganic light-emitting device may be reduced.

Accordingly, a second healing process is performed to remove a regionhaving a weak binding force between the environmental element 51 or 51′and the LVT inorganic material or among the LVT inorganic materials, byaccelerating vigorous substitution reaction between the environmentalelement 51 or 51′ and the LVT inorganic material and among the LVTinorganic materials, and improving heat resistance and mechanicalstrength of the inorganic layer 4.

The second healing process may be performed by using a chemicaltreatment, a plasma treatment, a hot chamber treatment including oxygen,or a hot chamber treatment including oxygen and moisture.

In one embodiment, the second healing process may be performed by usinga chemical treatment by which the inorganic layer 4 is treated with atleast one of an acidic solution, an alkaline solution, or a neutralsolution. In this regard, the alkaline solution may be a nitratesolution, e.g., a potassium nitrate solution.

In another embodiment, the second healing process may be performed byusing a plasma treatment by which the inorganic layer 4 is treated usingat least one of an O₂ plasma, a N₂ plasma, or an Ar plasma in a vacuum.

In another embodiment, the second healing process may be performed byusing a plasma treatment by which the inorganic layer 4 is treated usingat least one of an O₂ plasma, a N₂ plasma, or an Ar plasma underatmospheric pressure.

In another embodiment, the second healing process may be performed byexposing the inorganic layer 4 to a chamber having an oxygen partialpressure in the range of about 2% to about 100%, for example, an oxygenpartial pressure in the air, and a temperature in the range of about 25°C. to about 150° C.

In another embodiment, the second healing process may be performed byexposing the inorganic layer 4 to a chamber having an oxygen partialpressure in the range of about 2% to about 100%, for example, an oxygenpartial pressure in the air, a relative humidity in the range of about10% to about 100%, and a temperature in the range of about 25° C. toabout 150° C.

The oxygen partial pressure is represented with respect to 100% of thepressure of the chamber.

In several embodiments, the healing process may not include theabove-described two steps, and only the first healing process may beperformed.

In various embodiments, the transiting may also be performed byirradiating the pre-inorganic layer 4″ with laser beams, and thenscanning the pre-inorganic layer 4″ with the laser beams. That is, thetransiting may be performed by increasing the temperature of thepre-inorganic layer 4″ by irradiating the pre-inorganic layer 4″ withlaser beams, and accordingly providing fluidity to the pre-inorganiclayer 4″.

Then, as shown in FIG. 6H, a laser beam is applied from the outside ofthe second substrate 11 to irradiate the second organic layer 32 toseparate the second organic layer 32 from the second substrate 11. Thelaser beam may be focused on the interface between the second substrate11 and the second organic layer 32 by adjusting a depth of the laserbeam, and irradiated to the entire surface of the upper surface of thesecond substrate 11. For example, the laser beam may have a wavelengthof 308 nm generally used in an excimer laser annealing (ELA) processthat is a silicon crystallization process. In this regard, since thesurface of the second organic layer 32 absorbs the laser beam at theinterface between the second organic layer 32 and the second substrate11, the surfaces thereof are partially burned so that the secondsubstrate 11 and the second organic layer 32 are separated from eachother.

In order to rectify or repair edge defects or separation defectsgenerated in the separation process of the second substrate 11 and thesecond organic layer 32, a heat-treatment may further be performed afterthe laser beam is irradiated.

Then, as shown in FIG. 6I, the second substrate 11 and the mothersubstrate 1′ are cut along cutting lines 13 to prepare individualdevices as shown in FIG. 6J.

Then, although not shown herein, a separate organic layer may further beformed to cover the inorganic layer 4 and/or the second organic layer32. If the separate organic layer is formed to cover the inorganic layer4 and/or the second organic layer 32, bending characteristics andstructural strength of the organic light-emitting device may beimproved. The formation of the organic layer may be applied to themother substrate 1′ right after the second substrate 11 is separatedtherefrom or to individual devices. Examples of the organic materialinclude an acrylic organic material or a polyimide that may or may notbe transparent.

The formation of the inorganic layer 4 performed using the secondsubstrate 11 via transition may be more efficient than a method ofdirectly forming the inorganic layer 4. That is, since the secondsubstrate 11 on which the pre-inorganic layer is formed is preparedusing a different process and/or in a separate location from the mothersubstrate 1′ on which the organic emission unit is formed, and then theinorganic layer is transited by bonding the second substrate 11 and themother substrate 1′, productivity may be improved and/or processing timemay be reduced when compared with a process of directly forming thepre-inorganic layer on the mother substrate 1′ on which the organicemission unit is formed. This effect may also be obtained according tothe following embodiments.

Here, the second substrate 11 and the mother substrate 1′ are separatedfrom each other according to the previous embodiment, but the presentinvention is not limited thereto. If desired, the bonding between thesecond substrate 11 and the mother substrate 1′ may be maintained.

For example, as shown in FIG. 7, the first substrate 1 and the secondsubstrate 11 are fixed to each other by disposing the adhesive 12 tosurround the organic emission unit 2. In this regard, the bondingbetween the second substrate 11 and the second organic layer 32 may bemaintained. Accordingly, sealing characteristics may further beimproved, and the second substrate 11 may provide additional strength.

For example, as shown in FIG. 8, the second substrate 11 may be cut andmaintained in a state bonded to the second organic layer 32. In thiscase, the second substrate 11 may provide additional strength.

As such, if the second substrate 11 is not separated from the mothersubstrate 1′, the laser beam does not pass through the second substrate11, so that the second substrate 11 may not be transparent. Accordingly,the second substrate 11 may be an opaque glass substrate, a plasticsubstrate, or a metallic substrate.

FIG. 9 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention.

The organic light-emitting device of FIG. 9 does not include the secondorganic layer 32 of FIG. 1, but includes a first organic layer 31 thatcovers the organic emission unit 2 and an inorganic layer 4 that coversthe first organic layer 31.

FIGS. 10A to 10H are diagrams for describing a method of preparing theorganic light-emitting device of FIG. 9. Description of the organiclight-emitting device which are the same as those shown in FIGS. 6A to6J will not be repeated here.

First, as shown in FIG. 10A, at least one pre-inorganic layer 4″ isformed on the second substrate 11. The pre-inorganic layer 4″ isdescribed above. In this regard, the pre-inorganic layer 4″ may furtherinclude a material having a laser beam absorption property such that itcan be separated from the second substrate 11, which will be describedbelow. The second substrate 11 formed of a glass material may absorblaser beams having different wavelengths.

Then, as shown in FIG. 10B, the adhesive 12 is applied to edge portionsof the second substrate 11.

As shown in FIG. 10C, a mother substrate 1′ on which the organicemission units 2 and the first organic layers 31 are formed is prepared,and then the mother substrate 1′ is disposed opposite to the secondsubstrate 11.

Then, as shown in FIG. 10D, the mother substrate 1′ and the secondsubstrate 11 are bonded in a vacuum, and UV rays are irradiated theretoto cure the adhesive 12. In this regard, each of the first organiclayers 31 is in contact with a corresponding one of the pre-inorganiclayers 4″.

Then, as shown in FIG. 10E, the pre-inorganic layers 4″ having fluidityby a transition process cover the first organic layers 31 to form theinorganic layers 4 that are in contact with the surface of the mothersubstrate 1′.

As shown in FIG. 10F, the interface between the second substrate 11 andthe inorganic layer 4 is irradiated with a laser beam to separate theinorganic layer 4 from the second substrate 11.

Then, as shown in FIG. 10G, the second substrate 11 and the mothersubstrate 1′ are cut along cutting the lines 13 to prepare individualdevices as shown in FIG. 10H.

Then, although not shown herein, a separate organic layer may further beformed to cover the inorganic layer 4. In this regard, the organiclight-emitting device may have the same structure as that of FIG. 4. Ifthe separate organic layer is formed to cover the inorganic layer 4,bending characteristics and structural strength of the organiclight-emitting device may be improved. The formation of the organiclayer may be applied to the mother substrate 1′ right after the secondsubstrate 11 is separated therefrom or to individual devices. Examplesof the organic material may include an acrylic organic material or apolyimide that may or may not be transparent.

The second substrate 11 and the mother substrate 1′ can be separatedfrom each other similar to the previous embodiment, but the presentinvention is not limited thereto. If desired, the bonding state betweenthe second substrate 11 and the mother substrate 1′ may be maintained.

For example, as shown in FIG. 11, the first substrate 1′ and the secondsubstrate 11 are fixed to each other by disposing the adhesive 12 tosurround the organic emission unit 2. In this regard, the bonding statebetween the second substrate 11 and the inorganic layer 4 may bemaintained. Accordingly, sealing characteristics may further beimproved, and the second substrate 11 may provide additional strength.

In one embodiment, as shown in FIG. 12, the second substrate 11 may becut and maintained in a state bonded to the inorganic layer 4. In thiscase, the second substrate 11 may provide additional strength.

FIG. 13 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention.

The organic light-emitting device of FIG. 13 does not include the firstorganic layer of 31 FIG. 1, but includes an inorganic layer 4 thatcovers the organic emission unit 2 and a second organic layer 32 thatcovers the inorganic layer 4.

FIGS. 14A to 14I are diagrams for describing a method of preparing theorganic light-emitting device of FIG. 13. Descriptions of the organiclight-emitting device which are the same as those shown in FIGS. 6A to6J will not be repeated here.

First, as shown in FIG. 14A, at least one second organic layer 32 isformed on the second substrate 11. Then, pre-inorganic layers 4″ areformed on the second organic layers 32 as shown in FIG. 14B. Thepre-inorganic layers 4″ are described above.

Then, as shown in FIG. 14C, the adhesive 12 is applied to edge portionsof the second substrate 11.

As shown in FIG. 14D, a mother substrate 1′ on which the organicemission unit 2 is formed is prepared, and then the mother substrate 1′is disposed opposite to the second substrate 11.

Then, as shown in FIG. 14E, the mother substrate 1′ and the secondsubstrate 11 are bonded to each other in a vacuum, and UV rays areirradiated thereto to cure the adhesive 12. In this regard, each of theorganic emission units 2 is in contact with a corresponding one of thepre-inorganic layers 4″.

Then, as shown in FIG. 14F, the pre-inorganic layers 4″ having fluidityby a transition process cover the organic emission units 2 to form theinorganic layers 4 that are in contact with the surface of the mothersubstrate 1′.

As shown in FIG. 14G, the interface between the second substrate 11 andthe second organic layer 32 is irradiated with a laser beam to separatethe second organic layer 32 from the second substrate 11.

Then, as shown in FIG. 14H, the second substrate 11 and the mothersubstrate 1′ are cut along cutting lines 13 to prepare individualdevices as shown in FIG. 14I.

Then, although not shown herein, a separate organic layer may further beformed to cover the inorganic layer 4 and/or the second organic layer32. If the separate organic layer is formed to cover the inorganic layer4 and/or the second organic layer 32, bending characteristics andstructural strength of the organic light-emitting device may beimproved. The formation of the organic layer may be applied to themother substrate 1′ right after the second substrate 11 is separatedtherefrom or to individual devices. Examples of the organic material mayinclude an acrylic organic material or a polyimide that may or may notbe transparent.

Here, the second substrate 11 and the mother substrate 1′ can beseparated from each other similar to the previous embodiment, but thepresent invention is not limited thereto. If desired, the bonding statebetween the second substrate 11 and the mother substrate 1′ may bemaintained.

In one embodiment, as shown in FIG. 15, the first substrate 1 and thesecond substrate 11 are fixed to each other by disposing the adhesive 12to surround the organic emission unit 2. In this regard, the bondingstate between the second substrate 11 and the second organic layer 32may be maintained. Accordingly, sealing characteristics may further beimproved, and the second substrate 11 may provide additional strength.

In one embodiment, as shown in FIG. 16, the second substrate 11 may becut and maintained in a state bonded to the second organic layer 32. Inthis case, the second substrate 11 may provide additional strength.

As such, when the second substrate 11 is not separated from the mothersubstrate 1′, the laser beam does not pass through the second substrate11, so that the second substrate 11 may not be transparent. Accordingly,the second substrate 11 may be an opaque glass substrate, a plasticsubstrate, or a metallic substrate.

FIG. 17 is a schematic cross-sectional view of an organic light-emittingdevice according to another embodiment of the present invention.

The organic light-emitting device of FIG. 17 does not include the firstorganic layer 31 of FIG. 7, but includes an inorganic layer 4 thatcovers the organic emission unit 2.

FIGS. 18A to 18H are diagrams for describing a method of preparing theorganic light-emitting device of FIG. 17.

Description of the organic light-emitting device which are the same asthose shown in FIGS. 8A to 8H will not be repeated here.

First, as shown in FIG. 18A, at least one pre-inorganic layer 4″ isformed on the second substrate 11. The pre-inorganic layer 4″ isdescribed above. In this regard, the pre-inorganic layer 4″ may furtherinclude a material having a laser beam absorption property such that itcan be separated from the second substrate 11, which will be describedbelow. The second substrate 11 formed of a glass material may absorblaser beams having different wavelengths.

Then, as shown in FIG. 18B, the adhesive 12 is applied to edge portionsof the second substrate 11.

As shown in FIG. 18C, a mother substrate 1′ on which the organicemission units 2 are formed is prepared, and the mother substrate 1′ isdisposed opposite to the second substrate 11.

Then, as shown in FIG. 18D, the mother substrate 1′ and the secondsubstrate 11 are bonded to each other in a vacuum, and UV rays areirradiated thereto to cure the adhesive 12. In this regard, each of theorganic emission units 2 is in contact with a corresponding one of thepre-inorganic layers 4″.

Then, as shown in FIG. 18E, the pre-inorganic layers 4″ having fluidityby a transition process cover the organic emission units 2 to form theinorganic layers 4 that are in contact with the surface of the mothersubstrate 1′.

As shown in FIG. 18F, the interface between the second substrate 11 andthe inorganic layer 4 is irradiated with a laser beam to separate theinorganic layer 4 from the second substrate 11.

Then, as shown in FIG. 18G, the second substrate 11 and the mothersubstrate 1′ are cut along cutting lines 13 to prepare individualdevices as shown in FIG. 18H.

Then, although not shown herein, a separate organic layer may further beformed to cover the inorganic layer 4.

If the separate organic layer is formed to cover the inorganic layer 4,bending characteristics and structural strength of the organiclight-emitting device may be improved. The formation of the organiclayer may be applied to the mother substrate 1′ right after the secondsubstrate 11 is separated therefrom or to individual devices. Examplesof the organic material may include an acrylic organic material or apolyimide that may or may not be transparent.

Here, the second substrate 11 and the mother substrate 1′ can beseparated from each other similar to the previous embodiment, but thepresent invention is not limited thereto. If desired, the bonding statebetween the second substrate 11 and the mother substrate 1′ may bemaintained.

In one embodiment, as shown in FIG. 19, the mother substrate 1′ and thesecond substrate 11 are fixed to each other by disposing the adhesive 12to surround the organic emission unit 2. In this regard, the bondingstate between the second substrate 11 and the inorganic layer 4 may bemaintained. Accordingly, sealing characteristics may further beimproved, and the second substrate 11 may provide additional strength.

In one embodiment, as shown in FIG. 20, the second substrate 11 may becut and maintained in a state bonded to the inorganic layer 4. In thiscase, the second substrate 11 may provide additional strength.

As such, when the second substrate 11 is not separated from the mothersubstrate 1′, the laser beam does not pass through the second substrate11, so that the second substrate 11 may not be transparent. Accordingly,the second substrate 11 may be an opaque glass substrate, a plasticsubstrate, or a metallic substrate.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims, and theirequivalents.

What is claimed is:
 1. A method of preparing an organic light-emittingdevice, the method comprising: forming at least one pre-inorganic layercomprising a low temperature viscosity transition (LVT) inorganicmaterial on a second substrate; forming at least one organic emissionunit on a first substrate; applying an adhesive to edge portions of atleast one of the second substrate or the first substrate; bonding thesecond substrate and the first substrate using the adhesive such thatthe pre-inorganic layer and the organic emission unit face each other;and transiting the pre-inorganic layer to an inorganic layer to coverthe organic emission unit and to contact the first substrate byperforming a healing process on the pre-inorganic layer at a temperaturegreater than a viscosity transition temperature of the LVT inorganicmaterial, wherein the organic emission unit is entirely containedbetween the inorganic layer and the first substrate, and wherein theinorganic layer is spaced from the adhesive.
 2. The method of claim 1,further comprising separating the inorganic layer from the secondsubstrate.
 3. The method of claim 1, wherein the second substratecomprises glass, plastic, or metal.
 4. The method of claim 1, whereinthe forming of the pre-inorganic layer comprises: applying a pastecomprising a powder of the LVT inorganic material to the secondsubstrate; and sintering the paste.
 5. The method of claim 1, whereinthe forming of the pre-inorganic layer comprises: applying a dispersioncomprising a powder of the LVT inorganic material to the secondsubstrate by spraying; and heat-treating the dispersion.
 6. The methodof claim 1, wherein the bonding of the second substrate and the firstsubstrate is performed in a vacuum, under a reduced pressure, or in aninert atmosphere in which an influence of moisture or oxygen issubstantially eliminated, so that the space between the second substrateand the first substrate is substantially maintained in a vacuum.
 7. Themethod of claim 1, wherein the viscosity transition temperature of theLVT inorganic material is a minimum temperature capable of providingfluidity to the LVT inorganic material.
 8. The method of claim 1,wherein the viscosity transition temperature of the LVT inorganicmaterial is less than a minimum value of denaturation temperatures ofmaterials contained in the organic emission unit.
 9. The method of claim1, wherein the LVT inorganic material comprises a tin oxide.
 10. Themethod of claim 9, wherein the LVT inorganic material comprises at leastone selected from the group consisting of a phosphorus oxide, a boronphosphate, a tin fluoride, a niobium oxide, and a tungsten oxide. 11.The method of claim 1, wherein the LVT inorganic material comprises SnO;SnO and P₂O₅; SnO and BPO₄; SnO, SnF₂, and P₂O₅; SnO, SnF₂, P₂O₅, andNbO; or SnO, SnF₂, P₂O₅, and WO₃.
 12. The method of claim 1, wherein thetransiting is performed by heat-treating the pre-inorganic layer at atemperature between the viscosity transition temperature of the LVTinorganic material and a minimum value of denaturation temperatures ofmaterials contained in an organic emission layer of the organic emissionunit.
 13. The method of claim 1, wherein the transiting comprisesheat-treating the pre-inorganic layer at a temperature between about 80°C. and about 132° C. for about 1 to 3 hours.
 14. The method of claim 1,wherein the transiting is performed in a vacuum or in an inert gasatmosphere.
 15. The method of claim 1, wherein the transiting comprisesscanning the pre-inorganic layer while irradiating the pre-inorganiclayer with a laser beam.
 16. The method of claim 1, further comprisingforming at least one organic layer between the second substrate and thepre-inorganic layer.
 17. The method of claim 2, further comprisingforming at least one organic layer between the second substrate and thepre-inorganic layer, wherein the separating of the inorganic layer fromthe second substrate comprises separating the organic layer from thesecond substrate by irradiating the organic layer with a laser beam. 18.The method of claim 16, wherein the organic layer covers at least oneportion of the inorganic layer.
 19. A method of preparing an organiclight emitting device, the method comprising: forming at least onepre-inorganic layer comprising a low temperature viscosity transition(LVT) inorganic material on a second substrate; forming at least oneorganic emission unit on a first substrate; forming at least one firstorganic layer on both the first substrate and the organic emission unitto cover the organic emission unit; applying an adhesive to edgeportions of at least one of the second substrate or the first substrate;bonding the second substrate and the first substrate using the adhesivesuch that the pre-inorganic layer and the first organic layer face eachother; and transiting the pre-inorganic layer to an inorganic layer tocover the first organic layer and to contact the first substrate byperforming a healing process on the pre-inorganic layer at a temperaturegreater than a viscosity transition temperature of the LVT inorganicmaterial, wherein the organic emission unit is entirely containedbetween the inorganic layer and the first substrate, and wherein theinorganic layer is spaced from the adhesive.
 20. The method of claim 19,further comprising separating the inorganic layer from the secondsubstrate.
 21. The method of claim 19, wherein the second substratecomprises glass, plastic, or metal.
 22. The method of claim 19, whereinthe forming of the first organic layer comprises providing a curableprecursor, and curing the curable precursor.
 23. The method of claim 22,wherein the providing of the curable precursor is performed by using aflash evaporator.
 24. The method of claim 22, wherein the curing of thecurable precursor is performed by using UV rays, infrared rays, andlaser beams.
 25. The method of claim 19, wherein the forming of thepre-inorganic layer comprises: applying a paste comprising a powder ofthe LVT inorganic material to the second substrate; and sintering thepaste.
 26. The method of claim 19, wherein the forming of thepre-inorganic layer comprises: applying a dispersion comprising a powderof the LVT inorganic material to the second substrate by spraying thepowder; and heat-treating the dispersion.
 27. The method of claim 19,wherein the bonding of the second substrate and the first substrate isperformed in a vacuum, under a reduced pressure, or in an inertatmosphere in which an influence of moisture or oxygen is substantiallyeliminated so that the space between the second substrate and the firstsubstrate is substantially maintained in a vacuum.
 28. The method ofclaim 19, wherein the viscosity transition temperature of the LVTinorganic material is a minimum temperature capable of providingfluidity to the LVT inorganic material.
 29. The method of claim 19,wherein the viscosity transition temperature of the LVT inorganicmaterial is less than a minimum value of denaturation temperatures ofmaterials contained in the organic emission unit.
 30. The method ofclaim 19, wherein the LVT inorganic material comprises a tin oxide. 31.The method of claim 30, wherein the LVT inorganic material comprises atleast one selected from the group consisting of a phosphorus oxide, aboron phosphate, a tin fluoride, a niobium oxide, and a tungsten oxide.32. The method of claim 19, wherein the LVT inorganic material comprisesSnO; SnO and P₂O₅; SnO and BPO₄; SnO, SnF₂, and P₂O₅; SnO, SnF₂, P₂O₅,and NbO; or SnO, SnF₂, P₂O₅, and WO₃.
 33. The method of claim 19,wherein the transiting is performed by heat-treating the pre-inorganiclayer at a temperature between the viscosity transition temperature ofthe LVT inorganic material and a minimum value of denaturationtemperatures of materials contained in an organic emission layer of theorganic emission unit.
 34. The method of claim 19, wherein thetransiting comprises heat-treating the pre-inorganic layer at atemperature between about 80° C. and about 132° C. for about 1 to 3hours.
 35. The method of claim 19, wherein the transiting is performedin a vacuum or in an inert gas atmosphere.
 36. The method of claim 19,the transiting comprises scanning the pre-inorganic layer whileirradiating the pre-inorganic layer with a laser beam.
 37. The method ofclaim 19, further comprising forming at least one second organic layerbetween the second substrate and the pre-inorganic layer.
 38. The methodof claim 20, further comprising forming at least one second organiclayer between the second substrate and the pre-inorganic layer, whereinthe separating the inorganic layer from the second substrate comprisesseparating the second organic layer from the second substrate byirradiating the second organic layer with a laser beam.
 39. The methodof claim 37, wherein the second organic layer covers at least oneportion of the inorganic layer.